Estudo estrutural e funcional das proteínas ligadoras de ácidos graxos (FABP- Fatty Acid Binding Proteins) de Fasciola hepatica

As proteínas ligadoras de ácidos graxos (Fatty Acid Binding Proteins, FABPs) de parasitos têm um papel importante no processo de infecção por estes organismos. Por este motivo, estas proteínas são antígenos candidatos para vacina contra a infecção por Schistosoma mansoni e Fasciola hepatica. No presente trabalho foram caracterizadas FABPs de F. hepatica e comparadas com a proteína Sm14 de S. mansoni, a FABP de parasito melhor caracterizada, mediante análise de sequências e estruturas modeladas. Também foram clonadas, expressas e purificadas as FABPs tipo 1 e tipo 3 de F. hepatica. Os resultados do presente estudo indicam que a FABP tipo 3 de F. hepatica é relacionada estrutural, imunológica e funcionalmente com a Sm14, um candidato vacinal amplamente estudado. Devido à importância da Sm14 como alvo para o desenvolvimento de vacina para a esquistossomose, as características apresentadas pela FhFABP3 de F. hepatica apontam esta proteína como um candidato importante também para o desenvolvimento de uma vacina contra a fasciolose

Ontogenetic and temporal variability in the fat content and fatty acid composition of Atlantic herring (Clupea harengus) from the Bay of Fundy, Canada

Atlantic herring (Clupea harengus) is an ecologically and economically valuable species in many food webs, yet surprisingly little is known about the variation in the nutritional quality of these fish. Atlantic herring collected from 2005 through 2008 from the Bay of Fundy, Canada, were examined for variability in their nutritional quality by using total lipid content (n=889) and fatty acid composition (n=551) as proxies for nutritional value. A significant positive relationship was found between fish length and total lipid content. Atlantic herring also had significantly different fatty acid signatures by age. Fish from 2005 had significantly lower total lipid content than fish from 2006 through 2008, and all years had significantly different fatty acid signatures. Summer fish were significantly fatter than winter fish and had significantly different fatty acid signatures. For all comparisons (ontogenetic, annual, and seasonal) percent concentrations of omega-3, -6, and long-chain monounsaturated fatty acids were the most important for distinguishing between the fatty acid signatures of fish. This study underscores the importance of quantifying variation in prey quality synoptically with prey quantity in food webs over ontogenetic and temporal scales when evaluating the effect of prey nutritional quality on predators and on modeling trophic dynamics.

Changes in body composition and fatty acid profile during embryogenesis of quillback rockfish (Sebastes maliger)

We investigated developmental changes in the body compositions and fatty acid (FA) profiles of embryos and preparturition larvae of the quillback rockfish (Sebastes maliger). Comparisons of proximate composition data from early-stage embryos with data from hatched preparturition larvae taken from wild-caught gravid females indicated that embryos gain over one-third their weight in moisture while consuming 20% of their dry tissue mass for energy as they develop into larvae. Lipid contributed 60% of the energy consumed and was depleted more rapidly than protein, indicating a protein-sparing effect. Oil globule volume was strongly correlated with lipid levels, affirming its utility as an indicator of energetic status. FA profiles of early embryos differed significantly from those of hatched larvae. Differences in the relative abundances of FAs between early embryos and hatched larvae indicated different FA depletion rates during embryonic development. We conclude that some metabolically important FAs may prove useful in assessing the condition of embryos and preparturition larvae, particularly 20:4n-6, which cannot be synthesized by many marine fish and which is conserved during embryogenesis. Variability in body composition and energy use among rockfish species should be considered when interpreting any measures of condition.

New insights into the diets of harbor seals (Phoca vitulina) in the Salish Sea revealed by analysis of fatty acid signatures

Harbor seals (Phoca fvitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available informationon harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

Fatty acid composition of red drum maintained by fishmeal, fish oil substitutes in diets

Recent research by the authors evaluated strategies to reduce fishmeal and fish oil in diets for red drum by substituting terrestrial proteins and lipids while maintaining beneficial fatty acids with DHA supplements derived from marine algae. Results suggested fatty acid-enriched finishing diets can be used with growout diets containing little or no fishmeal and fish oil to achieve the desired DHA content in the final fish fillets.

Fatty acid composition of three species of Hypnea (Gigartinales, Rhodophyta) from Karachi coast

Hypnea musciformis (Wulf.) Lamour., H. pannosa J. Ag. and H. valentiae (Turn.) Mont., collected from the northern Arabian Sea coast of Pakistan, have been investigated for their fatty acid compositions through GC-MS. Palmitic acid was present in largest quantity (55-57%) and oleic was the major (7.6-8.4%) unsaturated fatty acid. Pentacosanoic and hexacosenoic acids are being reported for the first time from any species of Hypnea. The three species differed remarkably due to their habitat ecology.

Fatty acid composition of three species of freshwater fishes

Fatty acid composition of freshwater fish tilapia, (Tilapia mosambica), barbus (Barbus carnaticus) and Varal (Ophicephalus) is determined by gas-liquid chromatography. Varal contained the highest amount of C sub(20:5) acid compared to other 2 spp. Of the odd-numbered fatty acids C sub(17) was the predominant fatty acid present. Palmitic acid was found to have a lower level in these fish compared to marine fish. Barbus recorded unusually high percentage of 23.3% of C sub(18:2) acid.

Fatty acid composition of Anchoviella and Thrissocleus

A study was made to elucidate fatty acid composition of Anchoviella and Thrissocleus, and bring to light similarities with other clupeids. The results are tabulated. The polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, are the 2 major fatty acids in the phospholipid fraction of both fish. Myristic, palmitic and stearic acids are the major components of the nonphosphorylated fraction.

Influence of sex, spawning, starvation and water temperature on fatty acid composition in Tilapia mossambica

The influence of sex, spawning, starvation and water temperature on the fatty acid composition of Tilapia mossambica has been studied. Tilapia egg lipid was found to have unusually high percentage of C sub(22:6) fatty acids (9.09%) compared to body and intestinal lipids. The C sub(16:1) acid was much less in the egg lipids (3.5%) whereas it was 11% in the body lipids. There was no significant difference in the fatty acid composition of body and intestinal lipids of male and female tilapia. Starvation caused the presence of high content of lower fatty acids (C sub(6), C sub(8), C sub(30), C sub(12) and C sub(33)) in the body lipids. Water temperature also influenced the fatty acid composition of Tilapia; the difference was more significant in body lipids than in intestinal lipids.

Fatty acid composition of some brown seaweeds (Phaeophyta) from the coast of Karachi

Ten species of filamentous and multicellular thalloid algae (Phaeophyta) belonging to six genera of the class Dictyophyceae were collected from different seawater habitats of Karachi, Pakistan at the northern boundary of the Arabian Sea during September 1997 and July 1998. They were extracted in chloroform: methanol, saponified, subjected to column chromatography (CC, TLC), esterified and analysed for fatty acid (FA) composition initially by gas-liquid-chromatography (GLC) and finally by gas chromatography-mass spectrometry (GC-MS). Algae of the classes Laminariophyceae and Fucophyceae (Phaeophyta) displayed only a few SCFAs, PUFAs and substituted FAs, no VLCFA, C22 UFA, CFA, DCFA and monoynoic FA, large amount of C16:0, very large quantity of C18:1, very small RCCL and FA-diversity, C18 UFAs up to four DBs, C20 UFAs up to three DBs only. They were characterized by the largest amount of C18:1, lowest degree of unsaturation of C20 UFAs, lack of C22 UFAs, the shortest RCCL and the smallest FA-diversity as compared to other phyla.